Computed tomography comprises a known area of endeavor. CT scanning and processing typically provides a three-dimensional image (or images) of the inside of an object as typically derived from a large series of two-dimensional X-ray images taken around a single axis of rotation (though other energy sources or motion trajectories are also sometimes employed in related processes). In many cases the object rests atop a CT scan table that rotates about this axis of rotation during the scanning process.
Unfortunately, small inconsistencies and/or changes with respect to the various geometries of a CT platform can lead to erroneous processing results. This can include dynamic variations that occur over time. Some technicians use so-called calibration phantoms to compensate for such dynamic variations. Calibration phantoms typically comprise an object having a known shape (such as a pin shape) comprised of a known material.
Calibration phantoms are typically placed or fixed atop the CT scan table to the exclusion of any other object and then scanned like an ordinary object of interest. The corresponding processing platform then uses the known information regarding the calibration phantom to develop corresponding calibration information. The processing platform then uses this calibration information to compensate for detected geometric variations when subsequently scanning objects of interest other than calibration phantoms.
Though a very successful approach when properly utilized, the use of calibration phantoms in this way can contribute to overall delay and/or effective downtime for the CT platform. To avoid such results, technicians may elect to calibrate their equipment less frequently. This, however, can lead to less-accurate scanning results or higher artifact levels. The trade-off seems intractable—achieve greater productivity with less assured accuracy, or achieve greater assured accuracy with reduced productivity.
Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and/or relative positioning of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention. Certain actions and/or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required. The terms and expressions used herein have the ordinary technical meaning as is accorded to such terms and expressions by persons skilled in the technical field as set forth above except where different specific meanings have otherwise been set forth herein.